How do exposed layers of sedimentary rock in the Grand Canyon reveal clues about the geologic time scale?

a. The chemical composition of each layer indicates the conditions on Earth when the layer was deposited.
b. Fossils of soft-bodied animals are prevalent in sedimentary rock.
c. Radiometric dating using 14C of fossils in each layer can accurately predict their age up one million years ago.


d. The chemical composition of each layer can be determined by radiometric dating.
e. The oldest fossils are found near the surface, while the most recent fossils are found at deeper layers.


ANSWER: a

Biology & Microbiology

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